Semiconductor laser device

ABSTRACT

A semiconductor laser device includes a mounting board, a semiconductor laser element provided on the mounting board, and an optical member. The optical member is made of silicon having a first {110} plane, a first {100} plane that is adjacent to the first {110} plane, a second {110} plane, and a second {100} plane that is adjacent to the second {110} plane, with the second {100} plane being fixed on the mounting board, and the first {110} plane being covered by a reflective film to reflect laser light emitted from the semiconductor laser element.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a divisional application of U.S. patent applicationSer. No. 15/242,966 filed on Aug. 22, 2016. This application claimspriority to Japanese Patent Application No. 2015-165930 filed on Aug.25, 2015. The entire disclosures of U.S. patent application Ser. No.15/242,966 and Japanese Patent Application No. 2015-165930 are herebyincorporated herein by reference.

BACKGROUND

1. Technical Field

The present disclosure relates to a method for manufacturing an opticalmember, a method for manufacturing a semiconductor laser device and asemiconductor laser device.

2. Description of Related Art

There has been a need in recent years for making packages smaller andhigher in output in the optical field, and especially with semiconductorlasers. To this end, there has been proposed a semiconductor laserdevice in which one or more laser elements and optical members, such asan optical member having a 45-degree sloped surface, are disposed in asingle package, and the laser light that has been reflectedperpendicularly is collimated with a lens. Also, in an effort to supplyan inexpensive optical member having a 45-degree sloped surface, therehas been proposed a method for manufacturing an optical member having a45-degree sloped surface in which silicon is used and subjected to wetetching (for example, JP2000-77382A, JP2006-86492A and JP2010-522349A).

However, it is not easy to achieve both flatness and good angularprecision of the 45-degree sloped surface. Also, no method has yet beenestablished with which such a mirror can be manufactured by a simplemethod, and there has been a need for a method in which an opticalmember equipped with a sloped surface with a high degree of flatness canbe manufactured by a simple method. Also, there has been a need for amethod for suitably mounting such an optical member by a simple method.

SUMMARY

The following inventions are disclosed in the present disclosure.

A semiconductor laser device has a mounting board, a semiconductor laserelement provided on the mounting board, and an optical member made ofsilicon having a first {110} plane, a first {100} plane that is adjacentto the first {110} plane, a second {110} plane, and a second {100} planethat is adjacent to the second {110} plane, with the second {100} planebeing fixed on the mounting board, and the first {110} plane beingcovered by a reflective film to reflect laser light emitted from thesemiconductor laser element.

According to one embodiment of the present disclosure, an optical memberthat includes a good-quality reflective film on a main surface with highflatness, and that is easy to handle can be simply and preciselymanufactured, and a semiconductor laser device including the opticalmember can be manufactured. According to one embodiment of the presentdisclosure, a semiconductor laser device including a high-precisionoptical member can be provided.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1A and FIG. 1B are a schematic plan view and a schematic crosssection, respectively, illustrating an embodiment of mask patterns on asilicon substrate in the present disclosure;

FIGS. 2A to 2D are schematic cross-sectional views illustrating anembodiment of the method for manufacturing an optical member in thepresent disclosure;

FIG. 3 is a schematic plan view illustrating a surface of the opticalmember obtained with the method in FIGS. 2A to 2D;

FIG. 4A and FIG. 4B are a schematic plan view and an a-a′ line schematiccross sectional view, respectively, illustrating an embodiment of asemiconductor laser device in the present disclosure;

FIG. 5 is a schematic cross sectional view illustrating anotherembodiment of a semiconductor laser device in the present disclosure;

FIG. 6 is a schematic cross-sectional view of an optical member obtainedin another method in the present disclosure;

FIG. 7A and FIG. 7B are a schematic plan view and a schematic crosssectional view, respectively, illustrating an embodiment of maskpatterns on a silicon substrate in another method for manufacturing anoptical member in the present disclosure, and FIG. 7C is a schematiccross sectional view of the optical member thus obtained;

FIG. 8A and FIG. 8B are a schematic plan view and a schematic crosssectional view, respectively, illustrating an embodiment of maskpatterns on a silicon substrate in another method for manufacturing anoptical member in the present disclosure, and FIG. 8C is a schematiccross sectional view of the optical member thus obtained; and

FIG. 9 is a schematic cross sectional view illustrating anotherembodiment of a semiconductor laser device in the present disclosure.

DETAILED DESCRIPTION OF EMBODIMENTS

Embodiments of the present invention will be described below withreference to the accompanying drawings. In the following embodiments ofthe methods and the semiconductor laser devices that embody thetechnological concept of the present invention are just examples, andunless otherwise specified, the constituent parts discussed in theembodiments are not intended to limit the scope of the presentinvention. Further, constitutions described in examples and theembodiments can be employed in other examples and embodiments. The sizesand the arrangement relationships of the members in each of drawings areoccasionally shown exaggerated for ease of explanation.

Embodiment 1: Method for Manufacturing an Optical Member

A method for manufacturing an optical member of this embodiment includes

(a) providing a silicon substrate having a first main surface and asecond main surface of a {110} plane that are parallel to each other;

(b) forming mask patients on the first main surface and second mainsurface, each of the mask patterns having an opening extending in onedirection, so that the opening on the first main surface side and theopening on the second main surface side are disposed alternately, or sothat the opening on the second main surface side are disposed directlyunder the opening on the first main surface side;

(c) forming recesses having sloped surfaces in the first main surfaceside and the second main surface side by wet etching the siliconsubstrate using the mask patterns as masks; and

(d) forming a reflective film on the first main surface or the secondmain surface.

a: Providing of Silicon Substrate

A silicon substrate is prepared. The silicon substrate has a first mainsurface and a second main surface that are composed of {110} planes andparallel to each other. The second main surface of the silicon substraterefers to the main surface on the opposite side from the first mainsurface. Here, “{110} plane” refers to one (110) plane out of thecrystal lattice planes in a diamond structure of silicon, which iscrystal structure of silicon that is stable at normal temperature andpressure, and to all equivalent crystal planes. “Equivalent crystalplanes” means the family of equivalent crystal planes or facets definedby the Miller index. The first main surface and/or the second mainsurface of the silicon substrate is permitted to have an off angle ofabout ±2 degrees from the {110} plane. The off angle is preferablywithin a range of ±1 degree, and more preferably within a range of ±0.2degree.

The size and thickness of the silicon substrate can be suitably adjustedas dictated by the intended application of the optical member to beobtained, for example. It is preferable to obtain a plurality of opticalmembers from a single silicon substrate, and to this end the siliconsubstrate may have a length and/or width of from a few centimeters to afew dozen centimeters.

The silicon substrate is preferably of uniform thickness, but may have aportion where the thickness is different. The thickness of the siliconsubstrate can be, for example, from 100 μm to a few thousand microns,such as a range of 500 to 2000 μm.

b: Formation of Mask Patterns

Mask patterns are formed on each of the first main surface and secondmain surface of the silicon substrate. Each of the mask patterns has anopening. The term the “opening” here means an opening that extends inone direction. There may be just one opening in each main surface, orthere may be two or more. In any case, it is preferable for the openingsin the first main surface and the second main surface to be parallel toeach other.

The mask patterns are preferably formed so that the opening on the firstmain surface side and the opening on the second main surface side aredisposed alternately (i.e., the opening on the first main surface sideand the opening on the second main surface side do not overlap eachother in plan view), or so that the opening on the second main surfaceside is located directly under the opening on the first main surfaceside (i.e., the opening on the first main surface side and the openingon the second main surface side overlap each other in plan view).

The shape and size of the openings and the direction in which theyextend can be set as needed.

Examples of the direction in which the openings extend include the <100>direction, the <111> direction, and the <112> direction. As shown inFIGS. 1A and 1B, the <100> direction is particularly preferable. Usingthe <100> direction as the direction in which the openings extend makesit easy to obtain 45-degree sloped surfaces. Also, the openings canextend in a direction parallel to the first main surface and/or thesecond main surface.

Here, the “<100> direction” refers to a direction perpendicular to the(100) plane, which is one of the crystal lattice planes in a diamondstructure, which is crystal structure of silicon that is stable atnormal temperature and pressure, and to all directions that areperpendicular to equivalent crystal planes.

The shape of the openings is preferably striped. As long as one openingextends in one direction, the one opening may be linked to the otheropening extending in the other direction that intersects the oneopening. For example, the openings extending in the <100> direction maylink to openings extending in the <110> direction to form a latticepattern or an intersecting shape. The openings extending in the <100>direction has outer edges (both sides) that are preferably parallel tothe <100> direction. Also, the openings extending in the <110> directionhas outer edges (both sides) that are preferably parallel to the <110>direction.

The length of the opening extending in one direction can be suitably setaccording to the size of the silicon substrate being used. The width ofthe opening extending in one direction can be suitably set according tothe height of the sloped surfaces to be obtained in a subsequent step,etc. An example of the width of the opening is about 200 to 1000 μm. Thewidth of each of the openings may be the same or different between theopening on the first main surface side and the opening on the secondmain surface side. The less is the width of the opening, the greater isthe surface area of the main surface remaining after etching. Therefore,the surface area of the main surface with the smaller width of openingcan be kept large by making the opening width be different on the firstmain surface side and the second main surface side. Stable mounting canbe achieved by using this larger main surface as the optical membermounting surface. On the other hand, the effective reflecting surfacearea of the optical member can be increased by using the larger mainsurface as the surface on which the reflective film is formed.

As discussed above, the mask pattern may have an opening extending inone direction (such as the <100> direction), as well as an openingextending in a different direction (such as the <100> direction). In thecase that there is the opening extending in some other direction, thiswidth may be the same as or different from the width of the openingextending in the one direction. The sloped surfaces formed by theopening extending in some other direction are not related to thefunction of the optical member. Thus, the width of the opening extendingin some other direction is preferably less than the width of the openingextending in the one direction. This allows the surface area of thesilicon substrate to be used more effectively. Also, the openingextending in some other direction can be used as grooves for division.In this case, it is preferable for the opening in some other directionto be somewhat wider, such as about 50 to 500 μm.

The depth of the opening corresponds to the thickness of the maskpattern, and is about 0.1 to 1 μm, for example.

The spacing of adjacent openings can be set as desired, according to theintended size of the optical member. In the case that the mask patternsare formed so that the opening on the second main surface side islocated directly under the opening on the first main surface side, thespacing of adjacent openings is about 200 to 1000 μm, for example. Inthis case, the mask patterns are preferably formed so that, when viewedfrom the first main surface side, the center line along the direction inwhich the opening on the second main surface side extend is locatedwithin the opening on the first main surface side. More preferably, themask patterns are formed so that the center line along the direction inwhich the opening on the first main surface side extend coincides withthe center line along the direction in which the opening on the secondmain surface side extend in plan view. For example, the center line ofthe opening along the <100> direction on the first main surface sidepreferably coincides with the center line of the opening along the <100>direction on the second main surface side in plan view. This layoutmakes it easier to match up the lower ends of the recesses having slopedsurfaces formed by etching (discussed below). Consequently, when thelower ends of the recesses are used as the division points, the divisioncan be made perpendicular to the first main surface, which makes thedivision easier.

In the case that the mask patterns are formed so that the opening on thefirst main surface side and the opening on the second main surface sideare located alternately, the spacing between the opening on the secondmain surface side adjacent to the opening on the first main surfaceside, in a see-through view, is about 200 to 1000 μm, for example.

The mask patterns can usually be formed by a known method and frommaterials known in this field, such as forming a resist film or aninsulating film (an oxide film or nitride film of silicon, hafnium,zirconium, aluminum, titanium, lanthanum, or the like, or a composedfilm of these, etc.), and forming by means of photolithography andetching steps. It is particularly preferable for the material of themask patterns to be suitably selected according to the type of etchantused in the wet etching (discussed below).

The openings extending in some other direction maybe formed on both thefirst main surface and the second main surface of the silicon substrate,but also may be formed on just the first main surface or the second mainsurface of the silicon substrate.

c: Formation of Recesses Having Sloped Surfaces

The silicon substrate is subjected to wet etching using the maskpatterns as masks. This wet etching may be performed first on the firstmain surface and then on the second main surface, but it is preferableto perform wet etching simultaneously on both the first main surface andthe second main surface sides. This forms recesses having slopedsurfaces on both the first main surface and the second main surfacesides. Etching from both sides makes division of the silicon substrate(discussed below) easier.

The sloped surfaces may be any crystal plane. The shape of the recessesin cross sectional view may be U-shaped, V-shaped, one of these shapesin which the corners are rounded, or the like.

It is especially preferable to form sloped surfaces having a {100}plane. The sloped surfaces are preferably surfaces extending in the<100> direction and having an angle of inclination of 45 degrees to thefirst main surface and second main surface (that is, the {110} plane) ofthe silicon substrate. In other words, the sloped surfaces preferablyform an angle of 135 degrees to the first main surface of the siliconsubstrate. However, the {100} plane here is permitted to have an offangle of about ±2 degrees with respect to the {100} plane, and thus thesloped surfaces may be surfaces having an inclination angle of about45±2 degrees to the second main surface. The off angle is preferablywithin a range of ±1 degree, and more preferably within a range of ±0.2degree.

The etching is preferably wet etching, but any other etching method thatallows anisotropic etching to be performed may be employed.

The wet etching may be performed under any conditions so long as theabove-mentioned mask patterns are used as the masks and an etchant thatallows for anisotropic etching is used. Examples of the etchant includestetramethylammonium hydroxide (TMAH), potassium hydroxide, sodiumhydroxide, ethylene diamine pyrocatechol (EDP), hydrazine or a solutionmixture prepared by adding isopropanol to, or mixtures thereof. Theconcentration of the etchant can be suitably set after taking intoaccount the etching rate of the silicon substrate and so forth. The useof TMAH is particularly preferable. This is because TMAH has higheranisotropy in the etching of a {110} plane silicon substrate than otheranisotropic etchants, and sloped surfaces that are sloped byapproximately 45 degrees from the main surface can be formed on a {110}plane silicon substrate with a high degree of accuracy. TMAH is alsopreferable because it is easy to handle.

As to the etching conditions, when the etchant is TMAH, for example, thetemperature of the etchant is set to between 80 and 110 degreescentigrade, and immersion is performed for about 2 to 10 hours. Theimmersion time may be adjusted to obtain the desired amount of etching.

In the case that the opening extending in the <110> direction is formedin the mask pattern used here, the sloped surfaces that are formed willbe the {111} plane, and will be faces having an angle of inclination ofabout 35 degrees (see 11 d in FIGS. 8A to 8C). The angle here is alsopermitted to have an off angle of about ±2 degrees to the {110} plane.

In the case that the etching is further continued after these slopedsurfaces have been formed, the cross sectional shape formed by thesloped surfaces from opposing sides will become trapezoidal, and furtheretching will form V-shaped grooves. When trapezoidal, and preferablyV-shaped, grooves are formed, division (discussed below) will be easierat the bottom of the V, so etching is preferably continued untilV-shaped grooves are formed. For instance, when each of mask patterns isused that has openings in the <100> direction and the <110> direction asdiscussed above, the silicon substrate will cleave in neither the <100>direction nor the <110> direction, so it is preferable to use theV-shaped grooves as the starting point for the division. In particular,when the mask patterns are formed so that the opening on the second mainsurface side is located directly under the opening on the first mainsurface side, the lower ends of the V-shaped grooves produced by thesloped surfaces etched from the first main surface side and the secondmain surface side will be close together, but it is preferable not toetch to the extent that the lower ends link up. In forming a reflectivefilm in a subsequent step, the silicon substrate can be handled in awafer unit, and forming the reflective film all at once simplifies theprocess.

Alternatively, when the mask patterns are formed so that the opening onthe second main surface side is located directly under the opening onthe first main surface side, etching may be performed until the slopedsurfaces etched from the first main surface side and the second mainsurface side are linked. This makes it possible to omit the division atthe recesses of the silicon substrate (discussed below). In particular,as will be discussed below, forming a reflective film on the first mainsurface or the second main surface is effective when performed beforethe formation of the mask patterns in step (b) and the formation of therecesses having sloped surface in step (c).

The sloped surfaces are preferably formed to a depth of about a fewhundred microns to one thousand and some hundreds microns, andparticularly about 200 to 1000 μm, for example, from the first mainsurface of the silicon substrate.

In the case that a silicon substrate is used that has a first mainsurface of a {110} plane and a second main surface of a {110} plane thatare parallel to each other, then no matter in which direction theopenings of the mask patterns extend, ultimately recesses having twosloped surfaces whose cross sectional shapes are in line symmetry can beformed. Consequently, as will be discussed below, it is possible to formsurfaces that are flat and horizontal, with which the divided siliconsubstrate and optical members can be easily picked up with a suctionapparatus or the like.

d: Formation of Reflective Film

A reflective film is formed on the first main surface or second mainsurface of the silicon substrate. In the case that the reflective filmis formed on the sloped surfaces, it will be formed at the angle bywhich those surfaces are inclined, so there is the risk that it may behard to control the film thickness, but this problem can be avoided byforming the reflective film on the first main surface or the second mainsurface.

The reflective film can be formed from a material capable of reflectingat least 50% of the light from the semiconductor laser element, forexample. In other words, the reflective film can have a reflectance ofat least 50% at the emission wavelength of the semiconductor laserelement. When combined with a high-output semiconductor laser element(such as one with a light output of at least 1 W), this film ispreferably formed from a material capable of reflecting at least 80%,and forming it from a material capable of reflecting at least 90%, or atleast 95%, is more preferable. Examples include a single-layer orlaminate-structure film of gold, silver, copper, iron, nickel, chromium,aluminum, titanium, tantalum, tungsten, cobalt, ruthenium, tin, zinc,lead, and other such metals, as well as alloys of these (for instance,examples of aluminum alloys include alloys of aluminum and copper,silver, platinum, or other such platinum family metals). When thereflective film is made of a metal, then a single-layer film ofaluminum, gold, silver, or chromium is particularly preferable.

The reflective film may be a dielectric multilayer film in which two ormore types of dielectric are laminated, etc. A preferable dielectricmultilayer film is a DBR (distributed Bragg reflector) film. Examples ofthe dielectric film composing the DBR film include an oxide or nitridefilm containing at least one element selected from the group includingof silicon, titanium, zinc, niobium, tantalum and aluminum. Among them,a multilayer structure of the oxide film of silicon, zinc, niobium,tantalum and aluminum is preferable. The first layer of the reflectivefilm preferably has good adhesion to silicon. For instance, SiO₂ oranother such silicon-containing layer is believed to be suitable. Thedesired reflectivity can be obtained by adjusting the material andthickness of the various layers of the dielectric multilayer film.

It is particularly preferable for the reflective film to be formed by adielectric multilayer film. Compared to a reflective film composed of ametal, a dielectric multilayer film has high reflectivity with respectto the emission wavelength of the laser. That is, a reflectivity ofclose to 100% can be achieved. Consequently, an optical member with lowoptical absorption, that is, little heat generation, can be obtained. Asa result, a high-output semiconductor laser device can be obtained.Since the reflectivity of a dielectric multilayer film varies when thethickness of each layer changes, it is preferable to form the filmperpendicular to the formation surface in wafer state so that the filmcan be formed in the designed thickness. Therefore, the dielectricmultilayer film is more preferably formed on the first main surface orthe second main surface (the {110} plane) of the silicon substrate.

The thickness of the reflective film is, for example, from about a fewtenths of a micron to a few dozen microns, with about 0.1 to 10 μm beingpreferable, and about 0.3 to 7 μm being more preferable.

The reflective film can be formed by a known method such as vacuumdeposition method, ion plating method, ion vapor deposition (IVD),sputtering, ECR sputtering, plasma deposition, chemical vapor deposition(CVD), ECR-CVD method, ECR-plasma CVD Law, electron beam evaporation(EB) method and atomic layer deposition (ALD) method. Regardless of howthe film is formed, it is preferably formed perpendicular to theformation surface.

A reflective film that has excellent angular accuracy, flatness, etc.,and has good film quality in its reflecting function can be formed byforming the reflective film on the first main surface or second mainsurface that is composed of a {110} plane. As a result, the reflectionefficiency and durability of the optical member can be enhanced. Also,an optical member can be manufactured simply, easily, accurately, andefficiently. Furthermore, the manufacturing cost for the optical memberitself can be reduced.

As long as the quality of the reflective film is not compromised, theformation of the reflective film on the first main surface or the secondmain surface may be performed before the formation of the mask patternsin step (b) or the formation of the recesses having sloped surfaces instep (c). In performing wet etching, in the case where the reflectivefilm is in a state of being protected by the mask patterns, this willprevent degradation of the reflective film quality by the wet etching.The mask patterns are removed after the wet etching.

e: Division of Silicon Substrate

The silicon substrate is preferably divided in the recesses. As long asthe division is performed after the recesses have been formed, it may beperformed either before or after the formation of the reflective film.To simplify the process, preferably the reflective film is formed all atonce in a wafer unit, after which the division is performed.

The division of the silicon substrate is preferably performed along thesloped surfaces (that is, along one direction). For example, it ispreferably performed in a direction along the 45-degree sloped surfaces,such as in the <100> direction. As discussed above, when sloped surfacesare formed on the silicon substrate, recesses, such as grooves with atrapezoidal or V-shaped cross section, are formed by one sloped surfaceor two sloped surfaces. Accordingly, it is preferable to divide in therecesses, such as in trapezoidal or V-shaped grooves, so that thedivision runs long these recesses or grooves. It is particularlypreferable to divide along the lower ends of the V-shaped grooves. Sincethere are a number of openings in each of the mask patterns on the firstmain surface and the second main surface, dividing in this way allowsthe formation of optical members having two sloped surfaces.

In particular, in the case that the mask patterns are formed by theabove process so that the opening on the second main surface side islocated directly under the opening on the first main surface side, thelower ends of the recesses from both main surfaces will substantiallycoincide, so the division can be performed more accurately andstraightly.

In the case that the etching is performed by forming mask patternshaving openings extending in two directions as discussed above, divisionin two directions can be performed simply and accurately by usingrecesses produced by this etching for the division. The two directionsare, for example, the <100> direction and the <110> direction.

Regardless of whether or not there is etching in a direction extendingin the above-mentioned <110> direction, the division is preferablyperformed in a direction perpendicular to the direction along the slopedsurfaces, such as in the <110> direction. The division here may make useof grooves produced by etching in a direction extending in the <110>direction, or may make use of division-assisting grooves or cracks, aswill be discussed below.

In the division of the silicon substrate, division-assisting groovesand/or cracks are preferably formed and the substrate divided alongthem. These division-assisting grooves and/or cracks can be made byblade dicing, laser dicing, or another such known method. In particular,the use of laser dicing is preferable because it allows for internalworking of the material. This allows cracks to be formed oversubstantially the entire surface, regardless of how thick the materialis, and suppresses the generation of debris during division. When laserdicing that allows internal working is used, a laser dicing apparatusemits an internal working laser beam, forming cracks directly under theV-shaped grooves, after which these are used as the starting points todivide the silicon substrate with a breaker.

The size of the silicon substrate after division can be set as needed.For example, one side may measure 2.0 mm and the other side 1.0 mm. Theside in the <110> direction is preferably 2.0 mm, and the side in the<100> direction 1.0 mm.

EXAMPLE 2 Semiconductor Laser Device

A semiconductor laser device of this embodiment has, as shown in FIGS.4A and 4B, a mounting board 1, a semiconductor laser element 4 providedon the mounting board 1 and an optical member 15 that is composed ofsilicon having a first {110} plane 11 a, a first {100} plane 11 b thatis adjacent to the first {110} plane 11 a, a second {110} plane 11 c,and a second {100} plane 11 b that is adjacent to the second {110} plane11 c. The second {100} plane 11 b of the optical member 15 is fixed onthe mounting board, the first {110} plane of the optical member 15 iscovered by a reflective film 13. The optical member 15 is disposed at aposition that allows laser light emitted from the semiconductor laserelement 4 to be reflected.

Optical Member 15

The optical member 15 is a member that reflects the laser light emittedfrom a semiconductor laser element 4 in the intended direction. Theoptical member 15 is preferably composed of silicon (Si). Silicon hashigher thermal conductivity than a conventional optical member composedof quartz (called a prism), so it is particularly advantageous with ahigh-output laser in which the output of the semiconductor laser elementis 1 W or higher.

The optical member preferably has a {110} plane and a {100} plane ofsilicon. There are preferably two or more of each of these {110} planeand {100} plane. That is, the laser reflecting surface of the opticalmember 15 is preferably the {110} plane. The member may also have otherplanes. The {110} plane and {100} plane here are intended to permitinclination due to an off angle of about ±2 degrees. Furthermore, it ispreferable that the {100} plane is fixed on a mounting board, and the{110} plane is covered by a reflective film. Thus forming a reflectivefilm on the {110} plane allows for easy and accurate control of the filmthickness, and allows a reflective film of good quality to be formed.The {100} plane here can be a plane that is at an angle of 45 degrees tothe {110} plane.

The {110} plane corresponds to the first main surface and second mainsurface of the silicon substrate in the above-mentioned method formanufacturing an optical member, for example, and the {100} plane is asloped surface formed by etching using a mask pattern having an openingthat extend in the <100> direction.

The optical member 15 may be usually one in which the {110} planeserving as the reflecting surface is covered by a reflective film asdiscussed above.

The optical member 15 is disposed opposite the semiconductor laserelement 4. The opposing disposition in this case means that the opticalmember 15 is disposed opposite the optical member 15, on the reflectingsurface of the optical member 15, that is, on the surface covered by thereflective film, at a position that is illuminated with the laser lightemitted from the semiconductor laser element 4 and at which this lightcan be reflected. More specifically, the optical member 15 is disposedso that the reflecting surface of the optical member 15 is located on anextension of the light waveguide area, on the light emission surfaceside of the semiconductor laser element 4. For example, it is disposedso that the reflecting surface of the optical member is inclined withrespect to the end of the semiconductor laser element on the opticalmember side. This reflecting surface reflects the laser light, andallows the optical axis of the laser light emitted from thesemiconductor laser element 4 to be turned. In the case where the laserlight from the semiconductor laser element is emitted parallel to themain surfaces of the mounting board, then the angle formed by the slopedsurfaces and the main surfaces of the mounting board is 45±2 degree, andpreferably 45±1 degree, and more preferably 45±0.2 degree. This allowsthe light from the semiconductor laser element to move forward in adirection that is perpendicular to the mounting board 1.

As discussed above, with the optical member 15, the first main surfaceor the second main surface serves as a reflecting surface, which allowsa surface adjacent to this reflecting surface, such as the {100} plane,to be parallel to the surface of the mounting board 1, that is, to be ahorizontal surface. Accordingly, using this surface improves handlingproperties. For example, it can be picked up easily with any suctionapparatus or the like that is commonly used in this field.

As long as it has the above-mentioned reflecting surface, and preferablyas long as it has a mounting surface and a surface that is parallelthereto and that contributes to improving handling, the optical member15 can have any of various shapes. Examples include a polyhedral column,a truncated pyramid, and shapes that are a combination of these. Theoptical member 15 may have sloped surfaces that are inclined to the{110} plane (see 11 d in FIGS. 8A to 8C). The inclination angle of thesesloped surfaces to the {110} plane is less than the inclination angle ofthe {100} plane to the {110} plane, and is about 35 degrees, forexample.

With the optical member 15, the reflecting surface is preferablydisposed within about 10 to 150 μm from the semiconductor laser element,for example, and more preferably within about 20 to 100 μm.

Just one optical member 15 may be disposed on the mounting board, or aplurality of them may be disposed. In the latter case, they arepreferably disposed in a matrix, for example. Also, one optical member15 may be disposed for each semiconductor laser element, or just one maybe disposed for a plurality of semiconductor laser elements.

The optical member 15 is usually disposed on the mounting board 1 via ametal layer and/or an adhesive member. The metal layer may be disposedover a surface area less than the surface area and/or the fixing surfaceof the optical member 15, or may be disposed on the same surface area.Also, this layer may be disposed sticking out from the edges of thefixing surface of the optical member 15. This ensures a heat dissipationpath for the optical member 15.

The metal layer may be formed by a single layer of gold, silver,aluminum, or another such metal, or by a laminate that includes these.More specifically, examples include Ti/Pt/Au, Ni/Au, Ni/Pd/Au,Ni/Pd/Au/Pd, and other such laminates. In the case that the outermostsurface of the metal layer is gold, all of part of this gold may diffuseinto the adhesive member (discussed below), such as a gold-based solder.In this case, the diffused gold will function as an adhesive member. Themetal layer can be formed by vapor deposition, sputtering, plating, oranother such method that is known in this field. Sputtering can be usedto particular advantage.

Example of the adhesive member include those made of a metal materialsuch as Au-based solder material (AuSn-based solder, AuGe-based solder,AuSi-based solder, AuNi-based solder, AuPdNi based solder, etc.) andAg-based solder material (AgSn based solder). When an adhesive member isused, the bonding surfaces of the optical member and the mounting boardor metal layer are put together with the adhesive member in between,after which they are held together at a specific temperature andpressure. For instance, thermocompression bonding can be used. From thestandpoint of heat dissipation, the adhesive member is preferablydisposed over the entire surface between the optical member and themounting board or metal layer. A UV curing adhesive, a thermosettingadhesive, or another such adhesive agent may also be used.

Mounting Board 1

The semiconductor laser element 4, the optical member 15, and so forththat make up the semiconductor laser device are placed on the mountingboard 1. The mounting board 1 is also used to allow heat generated bythe semiconductor laser element 4 to be efficiently released to theoutside. The mounting board 1 is typically composed of an insulatingceramic. AlN, SiC and Alumina are an example of an insulating ceramic.With heat dissipation in mind, a metal member (copper, aluminum, etc.),an insulating ceramic of a different material, or the like may also bedisposed on the lower surface of the first insulating ceramic.

There are no particular restrictions on the thickness of the mountingboard 1, but an example is about 0.2 to 5 mm.

The shape or size of the mounting board 1 can be suitably adjustedaccording to the shape, size, and so forth of the intended semiconductorlaser device. Examples of the planar shape include rectangular and othersuch polyhedral shapes, circular, elliptical, and shapes that are closeto these. The mounting board 1 may have concave-convex or the like onits surface, but the surface is preferably flat. An example of themounting board 1 is a rectangular mounting board 1 in the form of a flatboard that measures about 2 to 30 mm along one side.

The mounting board 1 may have a wiring pattern on its surface. Terminalsmay also be provided for connecting to an external power supply. Awiring pattern or the like may be embedded inside the mounting board 1.The entire rear surface of the mounting board 1 can serve as a heatdissipation surface by providing terminals for connecting to an externalpower supply on the front of the mounting board 1.

Sub-Mount 3

A sub-mount 3 may be provided on the mounting board 1. The semiconductorlaser element 4 here is provided on the sub-mount 3. The sub-mount 3 isformed from a material with good thermal conductivity for the sake ofheat dissipation from the semiconductor laser element 4, and may beformed from a material whose thermal conductivity is higher than that ofsilicon. Examples thereof include AlN, CuW, diamond, SiC, and the like.Among them, the sub-mounts made of a single crystal of AlN or SiC arepreferred.

There are no particular restrictions on the thickness of the sub-mount3, but an example is about 100 to 500 μm, preferably about 120 to 400μm, and more preferably about 150 to 300 μm. In the case that thesub-mount 3 has at least a certain thickness, light from thesemiconductor laser element can be efficiently reflected by thereflecting member and taken off. The thickness of the sub-mount 3 may beenough for the light emission point of the semiconductor laser elementto be located higher than the lower end of the reflective film, forexample. The height of the semiconductor laser element is preferablysuch that the desired portion of the light emitted from thesemiconductor laser element (the portion of the optical intensity to bereflected) will fit on the reflective film.

There are no particular restrictions on the planar shape of thesub-mount 3, but examples include rectangular and other such polyhedralshapes, circular, elliptical, and shapes that are close to these. Thesize of the sub-mount 3 can be suitably adjusted to afford good heatdissipation and to match the characteristics of the semiconductor laserdevice that is ultimately to be obtained. For instance, the sub-mount 3has a surface area that is greater than the surface area of thesemiconductor laser element 4 in plan view. That is, the sub-mount 3 hasa length and width that are greater than the length and width of thesemiconductor laser element 4 in plan view. This allows all orsubstantially all of the semiconductor laser element 4 to be disposed onthe sub-mount 3, and ensures a heat dissipation path.

Just one sub-mount 3 may be disposed on the mounting board 1, or aplurality of them may be disposed. In the latter case, they arepreferably disposed in a matrix, for example.

The sub-mount 3 is usually disposed on the mounting board 1 via theabove-mentioned metal layer and/or adhesive member. The metal layer maybe disposed on a surface area less than the surface area of thesub-mount 3, or may be disposed on the same surface area. Also, thislayer may be disposed sticking out from the edges of the sub-mount 3.

Semiconductor Laser Element 4

The semiconductor laser element 4 has a function that, when voltage isapplied and current over a threshold value is supplied, light that hasbeen produced by the active layer and amplified in the light waveguidearea within a cavity is released as laser light to the outside. That is,laser generation occurs. This semiconductor laser element 4 can be anyknown laser element that is configured by laminating a plurality oflayers of semiconductor. For example, it can be an element in which ann-type semiconductor layer, an active layer, and a p-type semiconductorlayer are laminated in that order over a conductive substrate, and aninsulating film, electrodes, and the like are formed on the surface ofthe semiconductor layer. Group III-V compounds are an example of thematerial of the semiconductor layer, of which nitride semiconductors arepreferable.

The semiconductor laser element 4 is provided on the sub-mount 3. Thisallows heat generated from the semiconductor laser element 4 toefficiently escape through the sub-mount 3, etc., to the mounting board1. The semiconductor laser element 4 may be mounted junction up (faceup) so that the substrate side is the mounting surface, but ispreferably mounted junction down (face down). Junction down mountingallows the site where laser light is generated in the semiconductorlaser element 4 to be moved closer to the mounting board 1 and thesub-mount 3 below. Thus disposing the laser light generation site, whichis the portion where heat tends to be generated, closer to the mountingboard 1 and the sub-mount 3 allows heat to be dissipated moreeffectively. With junction down mounting, the semiconductor laserelement 4 is preferably disposed so that part of it sticks out from theend of the sub-mount 3 to the optical member 15 side. The protrusionlength can be about 10 to 20 μm, for example. This reduces thereflection of laser light by the sub-mount, and also shortens thedistance between the optical member 15 and the semiconductor laserelement 4 in a direction parallel to the surface of the mounting board.That is, the semiconductor laser element 4 can be moved closer to theoptical member 15 (discussed below). This further reduces the size ofthe semiconductor laser device.

Just one semiconductor laser element 4 may be disposed on each sub-mount3, or a plurality of them may be disposed on one sub-mount 3. Theplurality of semiconductor laser elements 4 may all have the samewavelength band, or may have different wavelength bands. Thesesemiconductor laser elements 4 may be installed in a matrix.

Cap

A cap 8 may be attached to the mounting board 1 so as to cover thesemiconductor laser element 4 and the optical member 15. Thesemiconductor laser element 4 is preferably sealed airtight by the cap8. In particular, when using a semiconductor laser element 4 that makesuse of a semiconductor material with an oscillation wavelength of about300 to 600 nm (such as a nitride semiconductor), organic matter,moisture, and the like will tend to collect, so providing the cap 8makes the interior of the laser device more airtight, waterproof, anddust-proof. Also, in this case members disposed in the interior that hasbeen made airtight by the cap 8 are preferably members that do notcontain any resin or other organic matter.

Examples of the shape of the cap 8 include that of a bottomed cylinder(a circular column, prismatic column, etc.), a truncated cone (atruncated circular cone, truncated pyramid, etc.), a dome, and modifiedshapes of these. The cap 8 can be formed from nickel, cobalt, iron,Ni—Fe alloys, KOVAR® (nickel-cobalt ferrous alloy), brass, and othersuch materials. The cap 8 provided to the mounting board 1 preferablyhas an opening provided on one surface thereof. A translucent member 7is provided to this opening. Laser light can be taken off from thetranslucent member 7. The cap 8 can be fixed to the mounting board 1 bya known method such as welding or soldering.

Lens

A lens serves to make the laser light into parallel light, to focus thislight, etc. The lens may be disposed in the forward direction of thelaser light reflected by an optical member mirror, or may be disposedbetween the semiconductor laser element and the optical member at thelocation illuminated by laser light from the semiconductor laserelement.

The lens can be formed from a material that transmits laser light, andany material that is commonly used can be used, such as quart, sapphire,or plastic. The light taken off from the semiconductor laser device ispreferably made into parallel light in order to accommodate variousapplications. Therefore, in order for the laser light to be emitted asparallel light from the semiconductor laser device, the use of acollimating lens is preferable. There are no particular restrictions onthe shape of the lens, but circular or elliptical is preferable. Thesize of the lens can be determined as needed according to the size andso forth of the laser beam that is emitted.

Embodiment 3: Method for Manufacturing Semiconductor Laser Device

A method for manufacturing a semiconductor laser device of thisembodiment includes fixing the optical member and a semiconductor laserelement, which are described above, to a mounting board so that laserlight emitted from the semiconductor laser element is directed at thereflective film of the optical member.

First the semiconductor laser element may be fixed to the mountingboard, and then the optical member fixed so that the laser light emittedfrom the semiconductor laser element will hit the reflective film of theoptical member, or the optical member may be fixed and then thesemiconductor laser element fixed so that the laser light will hit thereflective film of the optical member, or both may be fixed at the sametime.

Thus fixing the semiconductor laser element and the optical memberallows the laser light emitted from the semiconductor laser element tobe reflected in a different direction from the direction in which thelaser light is emitted.

When the optical member is fixed to the mounting board, the surface ofthe optical member that is to be opposite the semiconductor laserelement is preferably fixed at a 45-degree angle to the mounting boardsurface. To this end, the surface of the optical member to be oppositethe mounting board is preferably the {100} plane of the above-mentionedsilicon substrate, for example. This allows the {110} plane, which hasnot undergone the above-mentioned etching, to serve as the reflectingsurface. This {110} plane has no roughness or defects caused by etching,and is therefore more suited to being the reflecting surface. In thiscase, the {110} plane can be a reflecting surface that is inclined at anangle of 45 degrees to the mounting board surface.

As discussed above, when the optical member is fixed to the mountingboard, it is preferably fixed via a metal layer and/or an adhesivemember.

When the semiconductor laser element is fixed to the mounting board, itis preferable for the semiconductor laser element to be fixed to asub-mount, and this sub-mount fixed to the mounting board via a metallayer and/or an adhesive member, or for the sub-mount to be fixed to themounting board, and the semiconductor laser element to be fixed to thesub-mount. In this case, if the semiconductor laser element is mountedjunction down, as discussed above, it is preferable for part of thesemiconductor laser element to be disposed more to the optical memberside than the end of the sub-mount. The semiconductor laser element, thesub-mount, and the mounting board can be fixed via the above-mentionedmetal layer and/or adhesive member.

In the case where the optical member is fixed to the mounting board,after which the semiconductor laser element is fixed to the mountingboard, the position of the optical member can be verified as an imagewith a camera or the like, and the mounting position of thesemiconductor laser element can be determined by using the position ofthe optical member as a reference. This allows the semiconductor laserelement and the optical member to be mounted at the proper positions bya simple method.

The p-electrode and n-electrode of the semiconductor laser element aredisposed so as to be electrically connected to the anode terminal andthe cathode terminal, respectively, of the package that includes themounting board. For example, after the semiconductor laser element, thesub-mount, and the optical member have been fixed to the mounting board,the electrodes of the semiconductor laser element and the wiring patternof the sub-mount are electrically connected by wire bonding with thewiring pattern of the mounting board.

When the lens is mounted, positioning and bonding of the lens may beperformed as needed. After the mounting position of the lens has beendetermined, the lens is fixed at the desired position with an epoxyresin, an acrylic resin, or another such UV setting adhesive,thermosetting adhesive, or the like.

In the case where the semiconductor laser device is sealed with a cap,the cap may be bonded to the mounting board by resistance welding,soldering, or the like. This sealing can be performed in dry air, anitrogen atmosphere, or the like at the dew point minus 10 degrees orless. It is also preferable to pretreat the members by ashing, heattreatment, or another such method to remove the moisture and organicmatter that may be adhering to the members.

Examples of the method for manufacturing the optical member, the methodfor manufacturing the semiconductor laser device, and the semiconductorlaser device in the embodiments will now be described in specific termsthrough reference to the drawings.

EXAMPLE 1 Method for Manufacturing Optical Member

a: Preparation of Silicon Substrate

First, a silicon substrate 11 is prepared as shown in FIGS. 1A and 1B.This silicon substrate 11 has a {110} plane at a first main surface 11 aand a second main surface 11 c. The thickness of the silicon substrate11 is 500 μm, for example.

b: Formation of Mask Patterns

An SiO₂ film is formed with a CVD apparatus over substantially theentire surface of the first main surface 11 a and the second mainsurface 11 c of the silicon substrate 11. A mask-formation patternhaving openings in the <100> direction and the <110> direction is thenformed by photolithography, and the SiO₂ film is wet etched withbuffered hydrofluoric acid. This forms mask patterns 12 having openings12 a and 12 b that run in the <100> direction and the <110> direction,respectively. The mask patterns 12 are such that the width Q of each ofthe openings 12 a on the first main surface and the second main surfaceis 300 μm, and the width Z of each of the openings 12 b on the firstmain surface and the second main surface is 150 μm. The openings 12 a onthe second main surface side are located directly under the openings 12a on the first main surface side. The direction in which both openings12 a extend, that is, the center lines running along the <100>direction, coincide. The side length X in the <100> direction of each ofthe mask patterns is 500 μm, and the side length Y in the <110>direction of each of the mask patterns is 700 μm.

c: Formation of Sloped Surfaces

Next, as shown in FIG. 2A, using the mask patterns 12 as masks, the{110} planes, which are the first main surface 11 a and the second mainsurface 11 c of the silicon substrate 11, are wet etched for 240 minuteswith TMAH at 90 degrees centigrade. This exposes 45-degree slopedsurfaces with a depth of approximately 200 μm from the first mainsurface 11 a and the second main surface 11 c along the <100> direction.The surfaces opposite these 45-degree sloped surfaces are also 45-degreesloped surfaces, resulting in grooves with a substantially V-shapedcross section. The 45-degree sloped surfaces 11 b here are {100} planes.The wet etching is performed to go around and underneath the maskpatterns 12 as well.

At the same time, 35-degree sloped surfaces with a depth ofapproximately 150 μm are exposed from the first main surface 11 a alongthe <110> direction. The surfaces opposite these 35-degree slopedsurfaces are also 35-degree sloped surfaces, resulting in grooves with asubstantially V-shaped cross section.

After this, the mask patterns 12 are removed with buffered hydrofluoricacid as shown in FIG. 2B.

d: Formation of Reflective Film

As shown in FIG. 2C, a reflective film 13 is formed on the {110} plane,which is the first main surface 11 a, of the silicon substrate 11 thusobtained, by using an ECR apparatus to form an SiO₂ film/ZrO₂ film (75nm/50 nm) as an eight-pair laminated structure (with a total filmthickness of 1000 nm). The reflectivity of this reflective film 13 withrespect to light with a wavelength of 430 to 460 nm and an incidenceangle of 45 degrees is at least 99%.

e: Division of Silicon Substrate

Next, as shown in FIG. 2D, the silicon substrate 11 is divided along thecenter (the vertex portion of the V shape) of the V-shaped groovesetched in the <100> direction of the silicon substrate 11 to obtainbar-shaped silicon substrates 11 having division surfaces 11 f.

Optionally, the silicon substrate 11 is divided along the center (thevertex portion of the V shape) of the V-shaped grooves etched in the<110> direction of the silicon substrate 11 to form optical members 15from the small pieces of the silicon substrate 11.

This allows an optical member 15 to be formed from a silicon substrate11 whose planar shape is substantially rectangular. As shown in FIG. 3,this optical member 15 has two kinds of sloped surface, namely, two45-degree sloped surfaces (that is, 11 b {100} planes) and two 35-degreesloped surfaces (that is, 11 d), on the first main surface 11 a side.The 11 b {100} planes are linked to the 35-degree sloped surfaces 11 dby curved surfaces 11 e that are rounded, or by surfaces with aplurality of orientations in which the inclination angle graduallychanges, for example. The same applies to the second main surface side.

EXAMPLE 2 Semiconductor Laser Device

As shown in FIGS. 4A and 4B, the semiconductor laser device 10 in thisexample mainly has the mounting board 1, the sub-mount 3 provided on themounting board 1, the semiconductor laser element 4 provided on thesub-mount 3, and the optical member 15. The semiconductor laser element4 and the optical member 15 are sealed airtight by the cap 8.

The mounting board 1 is constituted by an insulating ceramic board 1 acomposed of an oblong piece of AlN, and a metal member 1 b composed ofcopper and disposed on the lower surface of this board.

Metal layers 2A and 2B are disposed on the upper surface of the mountingboard 1, apart from each other, and at the locations where thesemiconductor laser element 4 and the optical member 15 are installed.

The metal layer 2A is created by laminating titanium (0.06 μm) andplatinum (0.2 μm) in that order from the mounting board 1 side, and thisdisposed an Au—Sn-based eutectic solder (3 μm) on this. The metal layer2B is created by laminating titanium (0.06 μm), platinum (0.2 μm), gold(1 μm), and palladium (0.3 μm) in that order from the mounting board 1side, and the disposed an Au—Sn-based eutectic solder (3 μm) on this.

The optical member 15 is the optical member 15 obtained in Example 1,and is composed of silicon. The optical member 15 has four {100} planes,which are sloped surfaces 11 b that are sloped at 45 degrees to thefirst main surface 11 a and the second main surface 11 c. A reflectivefilm 13 having a laminated structure composed of an SiO₂ film and a ZrO₂film (75 nm/50 nm) is provided on the first main surface 11 a.

The sloped surfaces 11 b of the optical member 15 are fixed to themounting board 1 via the metal layer 2B. The height from the lowermostend to the uppermost end of the optical member 15, that is, the lengthbetween the opposing, parallel sloped surfaces 11 b, is 1000 μm.

The sub-mount 3 is made of AlN in which titanium (0.06 μm) and platinum(0.2 μm) have been laminated on the rear surface. The sub-mount 3 has acuboid shape measuring 450 μm×1900 μm×200 μm (thickness).

When the sub-mount 3 is mounted on the mounting board 1, titanium (0.0682 m), platinum (0.2 μm), an Au—Sn-based eutectic solder (3 μm),platinum (0.2 μm), and titanium (0.06 μm) are laminated in that orderfrom the mounting board 1 side, and the mounting is performed withheating.

The semiconductor laser element 4 is disposed on the sub-mount 3 via anAu—Sn-based eutectic solder, for example. The semiconductor laserelement 4 is a substantially rectangular element (150×1200 μm) with anoscillation wavelength of 445 nm, formed from a nitride semiconductor.

The end surface of the semiconductor laser element 4 on the opticalmember 15 side is disposed closer to the optical member 15 than the endsurface of the sub-mount 3 on the optical member 15 side. The distancebetween these end surfaces is 15 μm, for example.

The light emission surface of the semiconductor laser element 4 isopposite the reflecting surface of the optical member 15, and isdisposed about 100 μm away.

The cap 8 is fixed on the mounting board 1 so that the semiconductorlaser element 4 and the optical member 15 will be sealed airtight. Thecap 8 has an opening in its upper surface, and a translucent member 7made of glass is provided in this opening.

With this semiconductor laser device 10, a reflective film of good filmquality is disposed on either the first main surface or the second mainsurface, which has extremely superior flatness, and this allows asemiconductor laser device with excellent reflection efficiency anddurability to be obtained inexpensively.

Furthermore, since a pair of surfaces that are inclined to the firstmain surface and the second main surface and are parallel to each otherare very precisely controlled to be at a 45-degree angle to the firstmain surface and the second main surface, the optical member 15 can bestably fixed by one of these sloped surfaces. The other sloped surfacecan be parallel to the mounting board and the semiconductor laserdevice, that is, can be horizontal, and makes the optical member 15easier to handle with a suction apparatus or the like, and improvespickup and other aspects of work efficiency.

Also, since the majority of the semiconductor laser element 4 can bedisposed on the sub-mount 3, good heat dissipation by the sub-mount 3can be ensured. Furthermore, since the semiconductor laser element 4 andthe optical member 15 can be close together, the beam diameter of thelaser light can be kept small, and light of high brightness can beobtained.

EXAMPLE 3 Semiconductor Laser Device

As shown in FIG. 5, the semiconductor laser device 10A in this examplehas substantially the same configuration as the semiconductor laserdevice 10, except that a lens 6 is disposed between the optical member15 and the semiconductor laser element 4.

The lens 6 functions as a collimating lens for changing the lightemitted from the semiconductor laser element 4 into collimated light.

EXAMPLE 4 Method for Manufacturing Optical Member

With the method for manufacturing an optical member in this example, anoptical member 25 is formed by substantially the same method as inExample 1, except that in the formation of the sloped surfaces byetching, grooves are formed with a substantially V-shaped cross section(see FIG. 2C), after which the etching is allowed to proceed furtheruntil the grooves on both the first main surface side and the secondmain surface side are linked as shown in FIG. 6.

Thus, when the silicon substrate is divided, the division in the <100>direction of the silicon substrate 11 can be omitted, and thissimplifies the manufacturing process.

Also, with this optical member 25, in addition to the effect of theoptical member discussed above, the surface area of the sloped surfaces11 b can be somewhat larger than with the optical member 15. Thus, thesemiconductor laser device can be fixed more stably to the mountingboard, the optical member 15 can be handled more easily with a suctionapparatus or the like, and pickup and other aspects of work efficiencycan be improved.

EXAMPLE 5 Method for Manufacturing Optical Member

With the method for manufacturing an optical member in this example, thesame silicon substrate 11 is provided as in Example 1, and as shown inFIGS. 7A and 7B, mask patterns 32X and 32Y having openings that runalong the <100> direction and the <110> direction, respectively, areformed in the first main surface 11 a and the second main surface 11 cof the silicon substrate 11.

With these mask patterns 32X and 32Y, the widths of openings 32Xa and32Ya extending in the <100> direction are different. The width Q of eachof the openings 32Xa is 250 μm, and the width Q2 of each of the openings32Ya is 500 μm. The center lines that run along the <100> direction ofthe openings 32Xa and 32Ya are in mutually coinciding locations.

These masks are used to perform etching, the reflective film 13 isformed, and the silicon substrate 11 is divided just as in Example 1,which allows the optical member 35 shown in FIG. 7C to be obtained.

With this optical member 35, in addition to the effect of the opticalmember discussed above, the surface area of the sloped surfaces 11 b 1can be somewhat larger than the surface area of the sloped surfaces 11 b2, as compared to the optical member 15. Thus, when the sloped surfaces11 b 2 are used to fix the semiconductor laser device to the mountingboard, more stable mounting can be achieved.

Alternatively, when the sloped surfaces 11 b 1 are used to fix thesemiconductor laser device to the mounting board, a suction apparatus orthe like can be applied to the sloped surfaces 11 b 2, the opticalmember 15 can be handled even more easily, and pickup and other aspectsof work efficiency can be improved.

EXAMPLE 6 Method for Manufacturing Optical Member

With the method for manufacturing an optical member in this example, thesame silicon substrate 11 is provided as in Example 1, and as shown inFIGS. 8A and 8B, mask patterns 42X and 42Y having openings that runalong the <100> direction and the <110> direction, respectively, areformed in the first main surface 11 a and the second main surface 11 cof the silicon substrate 11.

With these mask patterns 42X and 42Y, the widths of openings 42Xa and42Ya extending in the <100> direction are different, but in asec-through view, the center lines that run along the <100> direction ofthe openings 42Xa and 42Ya alternate at regular intervals. The pitch ofthe openings on the first main surface 11 a and the second main surface11 c is twice that in Example 1.

These masks are used to perform etching, the reflective film 13 isformed, and the silicon substrate 11 is divided just as in Example 1,which allows the optical member 45 shown in FIG. 8C to be obtained,which also has the division surfaces 11 f.

With this optical member 45, in addition to the effect of the opticalmember discussed above, the surface area accounted for by the slopedsurfaces in the first main surface and the second main surface can bereduced, or more specifically, halved, so a larger surface area can beemployed for the first main surface and the second main surface thatserve as the reflecting surface. Thus, when applied to a semiconductorlaser device, a larger mounting margin can be afforded, which makes itsimpler to mount to the semiconductor laser device.

EXAMPLE 7 Semiconductor Laser Device

As shown in FIG. 9, the semiconductor laser device 40 in this examplehas substantially the same configuration as the semiconductor laserdevice 10, except that the optical member 45 is used instead of theoptical member 15.

With the method in this embodiment, it is easy to provide an opticalmember that is easy to handle, is inexpensive, is high in quality, andhas sloped reflecting surfaces, for a wide range of laser devices,regardless of the shape and size, such as low-cost compact semiconductorlaser devices and high-output semiconductor laser devices for whichdemand has been on the rise in recent years. Furthermore, asemiconductor laser device that makes use of the optical member thusobtained can be provided. In particular, this is suited to a surfacemounting type of semiconductor laser device. Also, the semiconductorlaser device in this embodiment can be widely applied to optical disks,optical communication systems, projectors, displays, printers,measurement devices, and other such devices.

What is claimed is:
 1. A semiconductor laser device comprising: amounting board; a semiconductor laser element provided on the mountingboard; and an optical member made of silicon having a first {110} plane,a first {100} plane that is adjacent to the first {110} plane, a second{110} plane, and a second {100} plane that is adjacent to the second{110} plane, a third {100} plane that is adjacent to the first {110}plane, and a fourth {110} plane that is adjacent to the second {110}plane, with the second {100} plane being fixed on the mounting board,the first {110} plane being covered by a reflective film to reflectlaser light emitted from the semiconductor laser element, the first{100} plane and the second {100} plane being parallel to each other, andthe third {100} plane and the fourth {100} plane being parallel to eachother.
 2. The semiconductor laser device according to claim 1, whereinthe first {110} plane and the second {110} plane are parallel to eachother, and the first {110} plane forms an angle of 45-degree to thesecond {100} plane.
 3. The semiconductor laser device according to claim1, wherein the reflective film is a dielectric multilayer film.
 4. Thesemiconductor laser device according to claim 1, wherein the opticalmember has a first division surface that connects the first {100} planeand the fourth {100} plane, and a second division surface that connectsthe second {100} plane and the third {100} plane.
 5. The semiconductorlaser device according to claim 1, wherein the semiconductor laserelement has a laminated structure in which a plurality of nitridesemiconductor layers are laminated.
 6. The semiconductor laser deviceaccording to claim 1, wherein an oscillation wavelength of thesemiconductor laser element is 300 to 600 nm.
 7. The semiconductor laserdevice according to claim 1, further comprising a cap attached to themounting board to cover the semiconductor laser element and the opticalmember.
 8. The semiconductor laser device according to claim 7, whereinthe semiconductor laser element and the optical member are sealedairtight by the cap.
 9. A semiconductor laser device comprising: amounting board; a semiconductor laser element provided on the mountingboard; and an optical member made of silicon having a first {110} plane,a first {100} plane that is adjacent to the first {110} plane, a second{110} plane, a second {100} plane that is adjacent to the second {110}plane, a first division surface that connects the first {100} plane andthe second {110} plane, and a second division surface that connects thesecond {100} plane and the first {110} plane, the first {100} plane andthe second {100} plane being parallel to each other, the second {100}plane being fixed on the mounting board, and the first {110} plane beingcovered by a reflective film to reflect laser light emitted from thesemiconductor laser element, and the first division surface and thesecond division surface being perpendicular to the first {110} plane.10. The semiconductor laser device according to claim 9, wherein thefirst {110} plane and the second {110} plane are parallel to each other,and the first {110} plane forms an angle of 45-degree to the second{100} plane.
 11. The semiconductor laser device according to claim 9,wherein the reflective film is a dielectric multilayer film.
 12. Thesemiconductor laser device according to claim 9, wherein thesemiconductor laser element has a laminated structure in which aplurality of nitride semiconductor layers are laminated.
 13. Thesemiconductor laser device according to claim 9, wherein an oscillationwavelength of the semiconductor laser element is 300 to 600 nm.
 14. Thesemiconductor laser device according to claim 9, further comprising acap attached to the mounting board to cover the semiconductor laserelement and the optical member.
 15. The semiconductor laser deviceaccording to claim 14, wherein the semiconductor laser element and theoptical member are sealed airtight by the cap.